Power semiconductor modules are used in high power applications to switch high voltages and currents and comprise multiple power semiconductors. Because each single semiconductor can have a maximum voltage and current, the power semiconductors have to be combined in parallel and/or in series within the power semiconductor modules to enable use in high power applications. To facilitate the manufacturing of such modules they commonly include (e.g., comprise) multiple substrates, on which the power semiconductors are mounted. The substrates are provided with common contacts for emitter, collector and base, so that the substrates can easily be connected within the power semiconductor modules.
FIG. 1 shows a schematic drawing of a substrate with multiple power transistors mounted thereon according to a known implementation. The substrate 1 includes a first metallization 3 which extends in two interconnected lines 5 extending along opposite edges 7 of the substrate 1. A second metallization 9 extends in an area 11 between the two lines 5 of the first metallization 3. The substrate 1 further includes a third metallization 13 with a gate contact 15 and a gate area 17, which are interconnected by means of a bonding wire 19. The gate area 17 of the third metallization 13 extends in the area 11 between the two lines 5 of the first metallization 3, thereby dividing the second metallization 9 in two legs 20. As can be seen in FIG. 1, multiple RC-IGBTs 21 are commonly mounted with their collectors on the first metallization 3. Emitter pads 23 of the RC-IGBTs 21 are bonded by means of bonding wires 19 to the second metallization 9, and gate pads 25 of the RC-IGBTs 21 are each bonded by means of a single bonding wire 19 to the third metallization 13.
The substrates can be mounted on a common base plate, which can be part of a housing of the power semiconductor module or which can be held within a housing of the power semiconductor module. Known power semiconductor modules, can be arranged such that four or six substrates are combined, each substrate being provided with four to six power semiconductors including power transistors like insulated gate bipolar transistors (IGBT) or reverse conducting insulated gate bipolar transistors (RC-IGBT), power diodes, or other power semiconductors suitable for high power applications. For example, a substrate can include four IGBTs and two power diodes.
Important characteristics of a power semiconductor module are size, heat generation, cooling and maximum power. To facilitate the use of power semiconductor modules, it is desired to provide modules with a compact size, which can involve little space for mounting, and which are capable of use with high currents.
DE 195 49 011 A1 discloses a substrate for mounting multiple power transistors thereon, with a first, second and third metallization. Furthermore, US 2002/0018353 A1 discloses a low-inductance circuit arrangement with two parallel metallizations with power transistors having the same orientation mounted thereon. Moreover, EP 0 455 322 A1 shows a semiconductor device with island-like gate metallization areas.